[Cfengine-develop] caching checksums with cfservd

[Luke A. Kanies]

Hi,

I'm getting to the point where I'm doing a lot of data transfer with 
cfservd, and I'd like to stop having cfservd force a checksum on every 
file transfer (as seen in cfservd.c where ChecksumChanged is passed 'true' 
as the value of 'refresh').

Would there be some problem if I made this change?  I know that I would 
need some kind of aging mechanism, but even if I could cache sums for five 
minutes I would see a performance benefit, because I'm looking at having 
hundreds of machines connect and get checksums for hundreds of files, 
possible up to hundreds of MB of data, and in the space of about half an 
hour.  If I could cache those sums, I would be much much much happier.

Any idea how hard it would be to make this work?  Maybe force a stat if 
we're running inside cfservd, and only force a sum if the stat shows a 
difference?

Luke

--
If a `religion' is defined to be a system of ideas that contains
unprovable statements, then Godel taught us that mathematics is not
only a religion, it is the only religion that can prove itself to be
one.                                    -- John Barrow
---------------------------------------------------------------------
Luke Kanies | http://abstractive.org | http://reductiveconsulting.com